preanesthetic assessment and premedication

1. PREOPERATIVE ASSESSMENT AND
PREMEDICATION
DR GNAPIKA
ASST PROFESSOR
DEPARTMENT OF ANAESTHESIOLOGY
S V MEDICAL COLLEGE

40. Antihypertensive
medications
Continue on the day of surgery
Possible exception:
For patients undergoing procedures with major fluid
shifts, or for patients who have medical conditions in
which hypertension is particularly dangerous, it may be
prudent to discontinue ACEIs or ARBs before surgery.
Cardiac medications
(e.g., β-blockers,
digoxin)
Continue on the day of surgery
Thyroid medications Continue on the day of surgery
Anticonvulsant
medications
Continue on the day of surgery
Asthma medications Continue on the day of surgery
Steroids (oral and
inhaled)
Continue on the day of surgery
Statins Continue on the day of surgery
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41. Aspirin Consider selectively continuing aspirin
in patients where the risk of cardiac
events is felt to exceed the risk of
major bleeding. Examples would be
patients high-grade CAD or CVD. Low
dose aspirin can be continued.
Theinopyridines (e.g., clopidogrel,
ticlopidine)
Clopidogrel must be stopped 7 days
before surgery and 14 days for
ticlopidine. Do not discontinue in
patients who have drug eluting stent
until they have completed 12 months
of dual antiplatelet therapy and 1
month in bare metal stent.
Insulin Discontinue all short acting insulin.
Patient should take a one third of the
dose of long acting insulin on the day
of surgery.
Oral hypoglycemic agents Discontinue on the day of surgery.
Warfarin Discontinue 4 days before surgery
except for patients having cataract
surgery without a bulbar block.
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43. PREANAESTHETIC
MEDICATION
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44.  Preanaesthetic medication is the term applied to the
administration of drugs prior to anaesthesia so as to
make anaesthesia safer for the patient.
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45. GOALS
 Relief of Anxiety
 Sedation & Amnesia
 Analgesia
 Drying of airway secretions
 Prevention of autonomic reflexes
 Reduction of gastric fluid volume & Increase pH
 Antiemetic effects
 Facilitation of smooth anaesthesia
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46. BENZODIAZEPINES
 Most commonly applied drugs for preanesthetic medication.
 Goals: Anxiolysis
Sedation
Amnesia- anterograde
Reduction of PONV
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47. Midazolam:
 This is the most commonly used BZD.
 Route: PO, IM, IV
 Dose:0.5mg/kg orally with onset of action after 10-20 min.
 0.03-0.05mg/kg Intravenously with fast onset of action within 2-3 min.
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48.  Lorazepam is mostly used when prolonged and intense anxiolysis is
pursued such as in cardiac surgery.
 Dose: 2-4 mg IV.
 Slow onset of action and prolonged duration of action detract from its use
for short surgical procedures.
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49. OPIOIDS
 Used as preoperative medication when there is a need to provide
analgesia such as before institution of regional anaesthesia or in patients
having pain owing to their disease.
 Commonly used in combination with benzodiazepines in cancer surgeries
and cardiac surgeries.
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50. Morphine:
 Analgesia
 Sedation
 Decreases the undesirable increase in heart rate with surgical stimulus.
 Usually given as 0.1-0.2mg/kg intramuscularly and peak effect occurs
within 45-90 mins.
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51. Fentanyl:
 Rapid onset of action
 Better hemodynamic stability
 Suppression of stress response
 Dose: 2-5 mcg/kg IV
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52. Side effects- opioids:
 Respiratory depression
 Nausea and vomiting
 Delayed gastric emptying
 Pruritus
 Orthostatic hypotension
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53. Dexmedetomidine
 ἀ2 receptor agonist
 D -enantiomer of medetomidine
 ἀ2:1=1600:1
 S/E: Bradycardia, Hypotension
 Doses: Sedation-0.5mcg/kg bolus f/b0.1-1mcg/kg/hr infusion
 Premedication: 0.3-0.6mcg/kg
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54.  Preoperative fasting guidelines:
Clear liquids:2hrs
Breast milk:4hrs
Infant formula, Non human milk & lightmeal:6hrs
Heavy meal (fried and fatty foods):8hrs
Prophylaxis –Pulmonary aspiration
of gastric contents:
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55. Routine drug usage is not recommended but beneficial in patients with risk
factors.
 Full stomach
 GERD
 Hiatal hernia
 Presence of nasogastric tube
 Diabetic gastroparesis
 Pregnancy
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56. Drugs - reduce gastric fluid volume:
 H2 Antagonists and PPIs reduce gastric acid secretion.
 Ranitidine 150mg orally or 50mg intravenously in the night before surgery and
also in the morning on the day of surgery.
 Pantoprazole 40mg intravenously.
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57. Drugs to increase gastric pH:
Sodium citrate :
 Basic substance that neutralizes gastric acid and raise pH of gastric
contents.
 1gm neutralizes 10meq Hcl.
 Short duration of action.
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58. Anticholinergics
 Goals:
Antisialogogue
Prevention of harmful vagal reflexes.
 Anticholinergic premedication was mandatory in the era of ether
anaesthesia.
 Less important with modern inhaled anesthetics.
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59.  Indications:
Pediatric population
Otorhinolaryngologic cases
Fiberoptic intubation
 Atropine- 0.02mg/kg IM or IV.
 Glycopyrrolate 4-8mcg/kg IM or 0.01mg/kg IV.
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60. Muscarinic anticholinergic drugs
Drug Duration CNS Antisialagog
e
Heartrate
Atropine Short Stimulation + ++
Glycopyrrolat
e
Long 0 ++ +
Scopolamine Short Sedation ++ 0/+
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61. Antiemetics
 Administered as prophylaxis against nausea and vomiting in patients at
risk like history of vomitings, gastric outlet obstruction.
 Ondansetron – 5 HT3 antagonist
4-8 mg IV
 Prokinetic drugs like Metaclopramide 10-20mg can also be given PO/IM/IV
 Uses: Aspiration prophylaxis, Vomitings
 Mechanism of action: Dopamine antagonist(D2), Cholinomimetic, 5HT3
antagonism
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62. Take Home :
 Preanesthetic assessment - guiding perioperative patient management,
reduces perioperative morbidity and enhances patient outcome
 Enhances OR efficiency
 Decrease day-of-surgery cancellations or delays
 Reduces hospital costs and enhance the quality of patient care
 Risk assessment and collaboration with surgeon and physician